The present invention relates to the provision of DNA sequences of group 4 major allergens from cereals (Triticeae). The invention also encompasses fragments, new combinations of partial sequences and point mutants having a hypoallergenic action. The recombinant DNA molecules and the derived polypeptides, fragments, new combinations of partial sequences and variants can be utilised for the therapy of pollen-allergic diseases. The proteins prepared by recombinant methods can be employed for in vitro and in vivo diagnosis of pollen allergies.
Type 1 allergies are of importance worldwide. Up to 20% of the population in industrialised countries suffer from complaints such as allergic rhinitis, conjunctivitis or bronchial asthma. These allergies are caused by allergens present in the air (aeroallergens) which are released by sources of various origin, such as plant pollen, mites, cats or dogs. Up to 40% of these type 1 allergy sufferers in turn exhibit specific IgE reactivity with grass pollen allergens, inter alia cereal pollen allergens (Freidhoff et al., 1986, J. Allergy Clin. Immunol. 78, 1190-2001). Of the cereal pollen allergens, the allergens of rye have particular importance.
The substances which trigger type 1 allergy are proteins, glycoproteins or polypeptides. After uptake via the mucous membranes, these allergens react with the IgE molecules bonded to the surface of mast cells in sensitised individuals. If two IgE molecules are crosslinked to one another by an allergen, this results in the release of mediators (for example histamine, prostaglandins) and cytokines by the effector cell and thus in the corresponding clinical symptoms.
A distinction is made between major and minor allergens, depending on the relative frequency with which the individual allergen molecules react with the IgE antibodies of allergy sufferers.
The allergens from the pollen of various species from the family of the grasses (Poaceae) are divided into groups which are homologous amongst one another.
In particular, the molecules of major allergen group 4 have high immunological cross-reactivity with one another both with monoclonal murine antibodies and also with human IgE antibodies (Fahlbusch et al., 1993 Clin. Exp. Allergy 23:51-60; Leduc-Brodard et al., 1996, J. Allergy Clin. Immunol. 98:1065-1072; Su et al., 1996, J. Allergy Clin. Immunol. 97:210; Fahlbusch et al., 1998, Clin. Exp. Allergy 28:799-807; Gavrovic-Jankulovic et al., 2000, Invest. Allergol. Clin. Immunol. 10 (6):361-367; Stumvoll et al. 2002, Biol. Chem. 383:1383-1396; Grote et al., 2002. Biol. Chem. 383:1441-1445; Andersson and Lidholm, 2003, Int. Arch. Allergy Immunol. 130:87-107; Mari, 2003, Clin. Exp. Allergy, 33 (1):43-51).
A complete DNA sequence is hitherto not known for any of the group 4 major allergens.
From the group 4 allergen from Dactylus glomerata, it has hitherto only been possible for peptides to be obtained by enzymatic degradation and sequenced:
DIYNYMEPYVSK,(SEQ ID NO 13) VDPTDYFGNEQ,(SEQ ID NO 14) ARTAWVDSGAQLGELSY(SEQ ID NO 15)and GVLFNIQYVNYWFAP.(SEQ ID NO 16,Leduc-Brodard et at.,1996, J. Allergy Clin.Immunol. 98: 1065-1072)
Peptides have also been obtained from the group 4 allergen of sub-tropical Bermuda grass (Cynodon dactylon) by proteolysis and sequenced:
KTVKPLYIITP,(SEQ ID NO 17) KQVERDFLTSLTKDIPQLYLKS,(SEQ ID NO 18) TVKPLYIITPITAAMI,(SEQ ID NO 19) LRKYGTAADNVIDAKWDAQGRLL,(SEQ ID NO 20) KWQTVAPALPDPNM,(SEQ ID NO 21) VTWIESVPYIPMGDK,(SEQ ID NO 22) GTVRDLLXRTSNIKAFGKY,(SEQ ID NO 23) TSNIKAFGKYKSDYVLEPIPKKS,(SEQ ID NO 24) YRDLDLGVNQWG,(SEQ ID NO 25) SATPPTHRSGVLFNI(SEQ ID NO 26)and AAAALPTQVTRDIYAFMTPYVSKNPRQ(SEQ ID NO 27AYVNYRDLD,Liaw et al.,2001, Biochem.Biophys. ResearchCommunication280: 738-743).
For Lolium perenne, peptide fragments having the following sequences have been described for the basic group 4 allergen: FLEPVLGLIFPAGV (SEQ ID NO 28) and GLIEFPAGV (SEQ ID NO 29, Jaggi et al., 1989, Int. Arch. Allergy Appl. Immunol. 89: 342-348).
As the first sequence of a group 4 allergen, the still unpublished sequence of Phl p 4 from Phleum pratense (SEQ ID NO 11) has been elucidated by the inventors of the present patent application and described in International Application WO 04/000881.
Nothing is hitherto known on the sequences of the group 4 major allergens from cereals (Triceae).
The object on which the present invention was based therefore consisted in the provision of DNA sequences of group 4 major allergens from cereals, in particular the allergen Sec c 4 from rye (Secale cerale) (SEQ ID NO 1, 3), Hor v 4 from barley (Hordeum vulgare) (SEQ ID NO 5) and Tri a 4 from wheat (Triticum aestivum) (SEQ ID NO 7, 9) and of corresponding recombinant DNA molecules on the basis of which the allergens can be expressed as protein and made available, as such or in modified form, for pharmacologically significant exploitation. The sequence of Phl p 4 (SEQ ID NO 11) was the starting point for the present invention.